Amplifiers come in many forms and are used in many applications. For example, amplifiers may be used with digital or analog signals, may be used in communications systems such as wireless telecommunications and satellite communications systems, and may be semiconductor-based or vacuum tube-based.
The performance demanded of amplifiers continues to increase, and many conventional amplifiers are failing to keep pace. For example, conventional semiconductor microwave amplifiers lack the power capabilities required by many modern microwave systems. As a result, vacuum tube power amplifiers, such as traveling wave tube amplifiers, are essential components of many modern microwave systems, including telecommunications, radar, electronic warfare, and navigation systems, because microwave tube amplifiers can provide microwave energy at levels of power higher by orders of magnitude in comparison to semiconductor microwave amplifiers. The higher power levels offered by tube devices are facilitated by the fact that electrons can travel at a much higher velocity in a vacuum than in a semiconductor. The higher velocity permits use of larger structures with the same transit time. Larger structures, in turn, permit greater power levels.
During operation of, for example, a radar system with a tube amplifier, the voltage supplied to the amplifier drops (or droops) due to the limited energy storage capacity of the power supply system that supplies power to the amplifier. Such a voltage drop may cause a phase shifting of the RF signal that is output from the amplifier. Such phase shifting may lead to, for example, target detection errors. One known solution to this problem is to add large capacitors and electromagnetic interference (EMI) shielding to the power supply. The capacitors may be combined with inductors to create a low pass filter that minimizes the high frequency ripple effect of the power supply. Such a solution often results in large or bulky power supplies. Also, such a solution does not address the issue of low frequency side-band power line induced spurious and low frequency side-band noise.
In one embodiment, the present invention is directed to a system including a component having a signal input and a power supply input, wherein the power supply input is in communication with a power supply. The system also includes a voltage probe connected between the power supply input and the signal input, wherein the probe injects a compensating signal into the signal input to compensate for variations in an output signal of the power supply over time.
In one embodiment, the present invention is directed to a system. The system includes a component having a signal input, a power supply input, and an electron source, wherein the power supply input is in communication with a power supply. The system also includes a voltage probe connected between the power supply input and the electron source, wherein the probe injects a compensating signal into the signal input to compensate for variations in an output signal of the power supply over time.
In one embodiment, the present invention is directed to a system. The system includes a first component having a signal input, a signal output, and a power supply input, wherein the power supply input is in communication with a first power supply. The system also includes a second component having a signal input and a power supply input, wherein the power supply input is in communication with a second power supply and wherein the signal input is connected to the signal output of the first component. The system further includes a voltage probe connected between the power supply input of the second component and the signal input of the first device, wherein the probe injects a compensating signal into the signal input of the first device to compensate for variations in an output signal of the second power supply over time.
In one embodiment, the present invention is directed to a method of compensating for unwanted phase changes at an output of a device. The method includes sensing a time-varying component of a signal output from a power supply and adding the time-varying component of the signal to an input signal of the device.
In one embodiment, the present invention is directed to an apparatus. The apparatus includes means for sensing a time-varying component of a signal output from a power supply and means for adding the time-varying component of the signal to an input signal of a device; wherein the adding compensates for unwanted phase changes at an output of the device.